(a) Field of the Invention
The present invention relates to a thin film transistor array panel and a method for manufacturing the same.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most popular flat panel displays (FPD). The liquid crystal display has two panels having electrodes for generating electric fields and a liquid crystal layer interposed therebetween.
The transmittance of incident light is controlled by the intensity of the electric field applied to the liquid crystal layer.
In the most widely used liquid crystal display, the field-generating electrodes are provided at both of the panels, and one of the panels has switching elements such as thin film transistors.
In general, a thin film transistor array panel is manufactured by photolithography using a plurality of photomasks. Since the photolithography process is expensive, the number of the photolithography steps needs to be minimized.
In order to prevent the delay or distortion of signals applied to wires, materials having a low resistivity, such as aluminum or aluminum alloy, are generally used. However, because of the poor contact properties between aluminum or aluminum alloy and indium tin oxide (ITO), which is used as a transparent electrode in a pad portion of a liquid crystal display, the aluminum or aluminum alloy is removed to prevent the corrosion of aluminum and aluminum alloy and a different material is then inserted therebetween. Accordingly, the manufacturing process is complicated and production costs are increased.
Also, it is desirable that a data wire transmitting image signals is made of aluminum or aluminum alloy. However, since such a data wire is connected to an ITO pixel electrode, the data wire is made of material having good contact properties such as chromium and molybdenum. Unfortunately, because material such as chromium and molybdenum has a higher resistivity than aluminum or aluminum alloy, signals are often delayed or distorted in a large scale liquid crystal display.
Also, when combining a completed thin film transistor panel and a completed color filter panel in the manufacturing process, if there are conductive particles between the two panels, the pixel electrode or the data wire of the thin film transistor panel and a common electrode of the color filter panel may be shorted.